A Generally, any time you manipulate semen, the per-cycle pregnancy rate decreases. The rate should be highest for fresh semen, then shipped semen, followed by frozen-thawed semen. This assumes a reproductively healthy mare and stallion. Per-cycle pregnancy rates with frozen-thawed semen are reported to range from 0 to 70%.

Therefore, it is important to do a little homework prior to choosing to use frozen semen. It is important to know the first-cycle pregnancy rate for that stallion’s frozen-thawed semen. This information is also important when using shipped-cooled semen. Next one needs to know how the mares were bred to achieve this pregnancy rate. Were the mares bred before, after, or before and after ovulation? Also, were the mares bred with a full dose (and what constitutes a full dose for that particular stallion) or was a dose split in half to allow breeding before and after ovulation? Was the semen deposited in the uterine body or was deep horn insemination used?

In order to achieve the stallion’s reported pregnancy rate, you must be able to repeat the breeding management used to obtain those rates